Heretofore a wide variety of approaches have been taken to aid person suffering a hearing loss. The most commonly used device is the audio ampification hearing aid. However, for persons suffering profoundly impaired hearing, such as in presbycusis, hearing loss in the elderly, there are adverse physiological implications to the use of audio amplification as the sole aid to hearing.
In order to assist individuals suffering a hearing loss, such as due to presbycusis, added stimulation has been provided to assist audio amplification. In particular, there have been developed numerous means for stimulating the skin in response to audio signals to provide a supplementary stimuli so that the individual can better distinguish various sounds. Such stimulators have included electrodes for providing a mild electrical shock, thermal varying sensors and vibrators. In some prior art applications, the tactile stimulators are activated in response to particular frequency components of the audio signal.
Despite the development of such devices to provide skin stimulation, difficulty for the individual to distinguish certain sounds in speech which are similar in many respects but have basically different frequency components has remained a problem. An example of sounds which are difficult for hearing impaired persons to distinguish are the s sounds in the words "six" and in "shoe". Similar problems exist for other sounds of this type. Therefore, there exists a need for a tactile stimulator which enables the individual to readily distinguish between sounds which are quite similar but have fundamental frequency differences and also have fundamental differences in meaning.